1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 2 /* */ 3 /* This file is part of the program and library */ 4 /* SCIP --- Solving Constraint Integer Programs */ 5 /* */ 6 /* Copyright (C) 2002-2021 Konrad-Zuse-Zentrum */ 7 /* fuer Informationstechnik Berlin */ 8 /* */ 9 /* SCIP is distributed under the terms of the ZIB Academic License. */ 10 /* */ 11 /* You should have received a copy of the ZIB Academic License */ 12 /* along with SCIP; see the file COPYING. If not visit scipopt.org. */ 13 /* */ 14 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 15 16 /**@file cons_linking.h 17 * @ingroup CONSHDLRS 18 * @brief constraint handler for linking binary variables to a linking (continuous or integer) variable 19 * @author Stefan Heinz 20 * @author Jens Schulz 21 * 22 */ 23 24 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 25 26 #ifndef __SCIP_CONS_LINKING_H__ 27 #define __SCIP_CONS_LINKING_H__ 28 29 30 #include "scip/def.h" 31 #include "scip/type_cons.h" 32 #include "scip/type_retcode.h" 33 #include "scip/type_scip.h" 34 #include "scip/type_var.h" 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 /** creates the handler for linking constraints and includes it in SCIP 41 * 42 * @ingroup ConshdlrIncludes 43 * */ 44 SCIP_EXPORT 45 SCIP_RETCODE SCIPincludeConshdlrLinking( 46 SCIP* scip /**< SCIP data structure */ 47 ); 48 49 /**@addtogroup CONSHDLRS 50 * 51 * @{ 52 * 53 * @name Linking Constraints 54 * 55 * @{ 56 * 57 * The constraints handler stores linking constraints between a linking variable (continuous or integer) and an array of binary variables. Such 58 * a linking constraint has the form: 59 * \f[ 60 * y = \sum_{i=1}^n {c_i * x_i} 61 * \f] 62 * with linking variable (continuous or integer) \f$ y \f$, binary variables \f$ x_1, \dots, x_n \f$ and offset \f$b \in Q\f$, and 63 * with the additional side condition that exactly one binary variable has to be one (set partitioning condition). 64 * 65 * This constraint can be created only with the linking variable, if it is an integer variable. In this case the binary variables are only created on 66 * demand. That is, whenever someone asks for the binary variables. Therefore, such constraints can be used to get a 67 * "binary representation" of the domain of the linking variable which will be dynamically created. 68 */ 69 70 /** creates and captures a linking constraint 71 * 72 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 73 */ 74 SCIP_EXPORT 75 SCIP_RETCODE SCIPcreateConsLinking( 76 SCIP* scip, /**< SCIP data structure */ 77 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 78 const char* name, /**< name of constraint */ 79 SCIP_VAR* linkvar, /**< linking variable (continuous or integer) which should be linked */ 80 SCIP_VAR** binvars, /**< binary variables */ 81 SCIP_Real* vals, /**< coefficients of the binary variables */ 82 int nbinvars, /**< number of binary starting variables */ 83 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? 84 * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */ 85 SCIP_Bool separate, /**< should the constraint be separated during LP processing? 86 * Usually set to TRUE. */ 87 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? 88 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 89 SCIP_Bool check, /**< should the constraint be checked for feasibility? 90 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 91 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? 92 * Usually set to TRUE. */ 93 SCIP_Bool local, /**< is constraint only valid locally? 94 * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */ 95 SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)? 96 * Usually set to FALSE. In column generation applications, set to TRUE if pricing 97 * adds coefficients to this constraint. */ 98 SCIP_Bool dynamic, /**< is constraint subject to aging? 99 * Usually set to FALSE. Set to TRUE for own cuts which 100 * are separated as constraints. */ 101 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? 102 * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */ 103 SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even 104 * if it may be moved to a more global node? 105 * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */ 106 ); 107 108 /** creates and captures a linking constraint 109 * in its most basic version, i. e., all constraint flags are set to their basic value as explained for the 110 * method SCIPcreateConsLinking(); all flags can be set via SCIPsetConsFLAGNAME-methods in scip.h 111 * 112 * @see SCIPcreateConsLinking() for information about the basic constraint flag configuration 113 * 114 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 115 */ 116 SCIP_EXPORT 117 SCIP_RETCODE SCIPcreateConsBasicLinking( 118 SCIP* scip, /**< SCIP data structure */ 119 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 120 const char* name, /**< name of constraint */ 121 SCIP_VAR* linkvar, /**< linking variable (continuous or integer) which should be linked */ 122 SCIP_VAR** binvars, /**< binary variables, or NULL */ 123 SCIP_Real* vals, /**< coefficients of the binary variables */ 124 int nbinvars /**< number of binary variables */ 125 ); 126 127 128 /** checks if for the given linking variable (continuous or integer) a linking constraint exists */ 129 SCIP_EXPORT 130 SCIP_Bool SCIPexistsConsLinking( 131 SCIP* scip, /**< SCIP data structure */ 132 SCIP_VAR* linkvar /**< linking variable (continuous or integer) which should be linked */ 133 ); 134 135 /** returns the linking constraint belonging the given linking variable (continuous or integer) or NULL if it does not exist yet */ 136 SCIP_EXPORT 137 SCIP_CONS* SCIPgetConsLinking( 138 SCIP* scip, /**< SCIP data structure */ 139 SCIP_VAR* linkvar /**< linking variable (continuous or integer) which should be linked */ 140 ); 141 142 /** returns the linking variable (continuous or integer) of the linking constraint */ 143 SCIP_EXPORT 144 SCIP_VAR* SCIPgetLinkvarLinking( 145 SCIP* scip, /**< SCIP data structure */ 146 SCIP_CONS* cons /**< linking constraint */ 147 ); 148 149 /** returns the binary variables of the linking constraint */ 150 SCIP_EXPORT 151 SCIP_RETCODE SCIPgetBinvarsLinking( 152 SCIP* scip, /**< SCIP data structure */ 153 SCIP_CONS* cons, /**< linking constraint */ 154 SCIP_VAR*** binvars, /**< pointer to store the binary variables array pointer */ 155 int* nbinvars /**< pointer to store the number of returned binary variables */ 156 ); 157 158 /** returns the number of binary variables of the linking constraint */ 159 SCIP_EXPORT 160 int SCIPgetNBinvarsLinking( 161 SCIP* scip, /**< SCIP data structure */ 162 SCIP_CONS* cons /**< linking constraint */ 163 ); 164 165 /** returns the coefficients of the binary variables */ 166 SCIP_EXPORT 167 SCIP_Real* SCIPgetValsLinking( 168 SCIP* scip, /**< SCIP data structure */ 169 SCIP_CONS* cons /**< linking constraint */ 170 ); 171 172 /** return all binary variable information of the linking constraint */ 173 SCIP_EXPORT 174 SCIP_RETCODE SCIPgetBinvarsDataLinking( 175 SCIP_CONS* cons, /**< linking constraint */ 176 SCIP_VAR*** binvars, /**< pointer to store binary variables, or NULL */ 177 SCIP_Real** vals, /**< pointer to store the binary coefficients, or NULL */ 178 int* nbinvars /**< pointer to store the number of binary variables, or NULL */ 179 ); 180 181 /** @} */ 182 183 /** @} */ 184 185 #ifdef __cplusplus 186 } 187 #endif 188 189 #endif 190